Muzzle sealing apparatus



Sept. 29, 1959 H. H. MoHAuP'r MuzzLE sEALING APPARATUs 2 sheBtS-Sheet 1med oct. 8, 1954 sept. 29, 1959 H. n. MOHAUPT MUzzLE SEALING APPARATUS 2Sheets-Sheet 2 1 VENT R. HEA/,ey H. n/fimO/pr Filed Oct. 8. 1954 'M razfVs.

United States Patent Ofifice 2,906,175 Patented Sept- 29, .1959

MUZZLE SEALING APPARATUS Henry H. Mohaupt, Fort Worth, Tex.

Application October 8, 1,954, Serial No. 461,231

2 Claiins. (Cl. 89-1) This invention relates to novel apparatus forsealing barrel muzzles yand particularly to apparatus for sealing thebarrel muzzles of penetrating tools 'adapted for use under submergedconditions and specifical'ly in wells.

In the recent past, therel has been developed for use in oil, gas andwater Wells a new process whereby the penertability of producing orpotential producing earth formations is increased. Such process includesthe firing into the formation of a missile possessed of extremely highkinetic energy, such missile being fired from a tool barrel andprincipally accelerating in a direction along the axis of the well bore,i.e., the barrel extends vertically down the well bore and the missileis fired therethrough. An application entilted Penetrating andFracturing T ool and filed January 25, 1954, in the name of Henry H.Mohaupt and having Serial No. 405,823 describes and claims such aprocess wherein directing means is used at the end of the tool barrel todirect the missile into thev formation.

Additional uses for a tool of the general nature described in theaforesaid aplication have been found, such uses for example comprisingthe vdestruction 'of objects within the .well such as tools droppedthereinto rand the like, and the `drilling of additional well bore byfiring the missile through ;strata relatively impervious to ordinary`drilling bits. v

In these applications the penetrating tool does not n01'- mally usemissile-directing means.

The aforesaid tool is characterized by the presence of a long barrel, arelatively massive missile and an exceedingly large powder vcharge andas stated above, upon being fired, the missile possesses tremendouskinetic energy. Inasmuch as the tool is normally fired submerged, it isnecessary to exclude fiuid from the barrel by some form of sealingmeans. Otherwise destruction of the barrel as by splitting and the likewould inevitably occur with consequent ruination of the tool. Even moreimportant, if fired unsealed, the tool' would in all likelihood lodgewithin the well in such manner as to. render it impossible of removal,requiring ahandonment of the well.

Heretofore it has been common practice to seal the muzzles of gunperforators used in Wells for lateral perforating, but the kinetic.energies involved in the use of gun perforators are only of the orderof 1500 ft.-lbs. per bullet, whereas the kinetic energies `involved inthe instant tool are of the order of several hundred thousand ft.-lbs.Moreover, the effective wall lthickness of the barrels used with gunperforators 'is several times the diameter Vof lthe bullets used and themass of the barrels as compared with that of the bullets is extremelyhigh. This combination of factors permits easy barrel sealing withoutdamage to the barrel upon transition of the missile therefrorn into thewell fluid. In the instant tool the diameter of the missile to be firedis conversely several times as thick as the barrel wall. Consequently ithas been found that conventional sealing means such4 as the afixing of adisc over the barrel muzzle and the like are inadequate for the 2purpose of efectively sealing the barrel muzzle while at thesame timepreventing damage thereto.

Such damage takes place for two principal reasons, the first of theseconstituting radial thrust. Such radial thrust is primarily caused bythe impact of the missile With the seal, which impact spreads apart theseal and hence the muzzle. Additionally, the pressure of the gasfollowing the missile contributes to this thrust, which thrust tends toswell, flare and split the barrel end and otherwise damage the barrelmuzzle or indeed lodge and wedge it against the well casing or well borewall in such manner as to prevent withdrawal of the tool from the wellafter use. The second principal cause of damage is the impact upon thetarget itself which causes'considerable amounts of debris to be fiungabout Within the well. Such debris if permitted to strike the barrelmuzzle tends 'to damage same considerably by impairing the adaptabilityof the muzzle to sealing and in effect destroys the tool for re-use. Asa co'rollary to this, damage may be caused upon firing the tool todestroy extraneous objects in the Well by virtue of rebound of the tooland subsequent impact of the barrel muzzle against portions of thedestroyed objects. I

It is therefore the principal object of this invention to provide anovel and effective sealing means adapted to use in conjunction with themuzzle end of a barrel adapted to fire a missile possessing extremekinetie energy under fluid.

It is another object of the nvention to provide such a sealing meanswhich will prevent damage to the muzzle end of the barrel as the missileis fired from the barrel.

It is another object of this invention to provide such a sealing meanswhich will protect the muzzle end of the barrel from radial thrustdamage and from flyfng dehris and the like caused by the firing ofthevmissilei lt is a further object of the invention to provide such asealing means which, during firing,V will protect the barrel muzzle fromrebounding impact against ext'raneous objects in the well.

lt is a further object of the invention to provide a sealing means ofvthe above nature but to which may he attached if desyired missiledirecting means yto `deflect a missile fired through the barrel from itsnormal course along the direction of said barrel. a

Other objects and purposes of the invention will be apparent from lthefollowing description. i

In the drawings: v

Fig. 1 shows a longitudinal sectional view of lthe sealing means of theinstant invention associated with the muzzle end of a barrel throughwhich is fired a missile possessing extreme kinetic energy; i I

Fig. 2 shows a missile being fired through the aforesaid sealing means;i

Fig. 3 shows varying degrees of damage incurred by the sealing meansupon passage of the missile therethrough; l

Fig. 4 shows a longitudinal sectional view of another embodiment of thesealing means of the instant invention which embodiment is afiixed tothe muzzle end of a somewhat modified barrel; and f i Fig. 5 shows thedamage inflicted to the aforesaid embodiment by virtue of passage of themissile therethrough.

In general, the invention of the instant application compn'ses provisionof sealing means for the muzzle end of a barrel through which is fired ahigh enei'gr missile which sealing means includes an impact wall spacedfrom the muzzle end of the barrel and which sealing means includes oneor more weakened portions adjacent to or spaced from the muzzle end ofthe barrel. The function of the spaced impact Wall is to provide anextended path for the missile lunobstructed by well fluid whereby theimpact of the missile With said impact wall and the transition of saidmissile from fluid-free passage to passage through the well fluid takesplace at a point well removed from the barrel muzzle, thus protectingthe muzzle from the deleterious effects of radial thrusts, fluid impactand 'associated transitional effects. The function of the weakenedportion or portions of the sealing means is to provide a break-off pointor points dissocated from the barrel muzzle to ensure that damage doneto the sealing means is not carried over to the barrel. Additionally,the effect of both the spaced impact wall and the weakened portions ofthe sealing means is to leave protective portions of said sealing meansin covering relationship to the barrel muzzle.

Referring specifically to Figs. l'to 3 inclusive, of the drawings, itwill be seen that the structure depicted shows a barrel having a muzzleend 12, said barrel being provided with threads 14. Threaded on to saidbarrel is an adapter 16 which like the barrel is nonexpendable and infact constitutes in effect an extension thereof. Sealing rings 18 areprovided to effect a fluid seal between the adapter and the barrel.

Intermediate its ends the adapter 16 includes an inner flange 20 havingan inside diameter approximating that of the inside diameter of thebarrel. Threads 22 are provided adjacent the outer end of the adapterand threaded thereonto is a sealing sleeve 24. The inner diameter ofsaid sealing sleeve preferably approximates the inner diameter of thebarrel 10 and the fiange 20 and sealing rings 26 and 28 provide a fluidseal between the adapter and the sealing sleeve.

The outer end of the sealing sleeve is counterbored to provide ashoulder 30 and a relatively thin side Wall 32 into which a sealing disc31 may be inserted, the edges of the wall 32 being adapted to be crimpedover to retain the sealing disc. Sealing rings 34 provide a fluid sealbetween the sealing disc and the sealing sleeve. It is thus seen thatthe sealing sleeve and sealing disc assembly comprise aV cup-shapedsealing cap having an impact face spaced from the barrel muzzle.

In assembly, the sealing rings 18 are placed in their respective groovesand the adapter 16 threaded to the barrel 10. Thereafter the sealingrings 26 and 28 are placed in their -respective grooves on the sealingsleeve 24 and said sealing sleeve threaded into the adapter 16. Thealuminum sealing disc 31 is assembled into place as previously noted.

As hereinabove stated, the missile 35 When fired from the barrel 10 pastthe adapter 16'and through the sealing sleeve 24- and sealing disc 31possesses extremely high kinetic energy. Since it is the purpose of thisinvention to protect the barrel 10 and its effective extension theadapter 16, it is desirable that radial thrust, debris, fluid hammereffect, and the like be avoided in the vicinity of the adapter 16. Dueto the spacing of the sealing disc 31 which .spacing is of preferably atleast one missile fdiarneter, the radial thrust indicated by the arrowsin 'I notable that in many cases such flaring will be insufiicient toextend the wall 32 as far as the outer diameter of the adapter 16 andhence the tool after firing may be freely withdrawn from the Well.

Again, condition B shows a shearing at a weak portion or highly stressedportion B of the thin wall 32 which may take place without substantialfiaring of the sealing sleeve 24. In this case little debris is left inthe well.,

Again, condition C shows considerable flaring of the sealing sleeve 24under which circumstances the thin Wall 32 may or may not have sheared.In the event that portions of the sealing means extend beyond the outerdiameter of the adapter 16, it is still possible to withdraw the toolfrom the well, upward movement of the tool merely bending back thedistorted sealing means.

Finally, under vthe most'severe conditions the sealing sleeve will breakat the highly stressed weakened portion D, it being noted that inwardlybeyond this point, the wall of the adapter 16 reinforces the sealingsleeve. In this event a greater amount of debris is left in the well,but more important, damage cannot extend to the adapter 16, thenon-expendable extension of the barrel 10.

It will be understood that the entire sealing sleeve is expendable asare those elements of the sealing means outwardly of the adapter 16.Inasmuch, however, as the inner threaded portion of the sealing sleeve24 remains within the adapter even under the most severe conditions ofdamage, the threaded sealing surface of the adapter is prevented fromdamage by flying debris, may not contact extraneous objects within thewell upon tool rebound, and is Well adapted for later re-use inconjunction with new sealing means.

It will be noted that recesses 36 are provided on the outer surface ofsealing sleeve 24. Such recesses are to accommodate set screws used vtoconnect a directing means such as is shown in co-pending applicationSerial No. 405 ,823 to which reference has been previously made. Suchdirecting means are used to defiect the missile from its normal flightin the direction of the barrel Where, for example, it is desired topenetrate the casing and formation With the missile. Since the directingmeans as with the sealing means is expendable, the operation of the saidsealing means is the same whether or not the directing means is used.

The embodiment of the invention shown in Fig. 4 does not utilize anadapter and finds special adaptation under 'conditions where availablespace dictates extremely small tool diameters. In this modification thebarrel 38 is provided with a muzzle portion 40 of reduced outsidediameter over Which portion is fitted a cup-shaped sealing cap 42 havingan extending cylindrical portion 43 and an impact face 44. Set screws 46are utilized to aflix the sealing cap 42 to the reduced diameter barrelportion 40 and sealing rings 48 provide a fluid seal between the sealingcap 42 and the barrel portion 40.

The bore 50 of the sealing cap should approximate in inner diameter theinner diameter of the bore of the barrel 38, but the sealing cap iscounterbored to provide a shoulder 52 abuttng against the muzzle end ofthe barrel and a thin wall 54 enveloping the portion 40 of the barrel.

Upon firing of the missile, impact and transition to well fluid do notoccur until the `forward end of the missile is well past the muzzle 'ofthe barrel, impact face 44 again being preferably Vat least one missilediameter from the muzzle end of the barrel. When such irnpact occurs,transitional effect and radial thrust are hence removed from the muzzle.

As shown in Fig. 5 in full outline A, Optimum well conditions may permitthe missile to pass through the sealing means without substantialflaring of the sealing cap 42. On the other hand, as shown in dottedoutline under condition B Wherein substantial flaring has occurred, itis still possible to withdraw the tool upwardly inasmuch as the cap hasbeen weakened and will bend back. Extreme stress, however, andunfavorable well conditions may result in complete breaking of thesealing cap whereby the sealing cap will part at the weakened portionindicated by the letter C. Inasmuch as point C represents a highlystressed point breaking will occur at this point and prevent fiaring orother damage to the portion 40 of the barrel. It is possible that someflaring or even breakage will occur at the thin wall portion 54 of thesealing cap 42 but such flaring or breakage will take place in effectivepoint of time subsequent to diminishment of the effect of the missiletransition to the fiuid and during that eritical period the thin wall 54protects the sealing surface of the barrel portion 40 from flyingfragments, debris and tool rebound.

It is apparent that other modifications may be devised incorporating thespirit and substance of the inventive features hereinabove disclosed,and it is understood that as to such modifications, applicant isentitled to the full breadth and scope of the appended claims.

I claim:

1. The combination with a non-expendable, elongated barrel adapted to bedisposed in a well under fiuid with the bore of the barrel extendingvertically down the well bore for repeated use in accelerating a missileto impart thereto a high kineticl energy and propelling the missile inthe well, of a sealing cap sealingly secured to the muzzle end of saidbarrel, said sealing cap having a sealing sleeve extending forwardly ofthe muzzle end of said barrel for a substantial distance and providing abore forming an extension of the barrel bore, said sealing sleeve beinglaterally unconfined for a substantial distance rearwardly from itsforward end and having a counter-bore in its forward end providing arelatively thin side wall, and a sealing disc inserted in and sealinglyretained in said counter-bore, said sealing disc being adapted to bepenetrated by the high kinetic energy missile and the laterallyunconfined section of said sealing sleeve being constructed and arrangedto absorb, by permanent deformation thereof, destructive energyoceasioned by the firing of said missile and the transition thereofthrough said sealing disc into well fluid, Whereby said barrel isprevented from being damaged.

2. The combination with a non-expendable, elongated barrel adapted to bedisposed in a well under fluid with the bore of the barrel extendingvertically down the well bore for repeated use in accelerating a missileto impart thereto a high kinetie energy and propelling the missile inthe well, of a sealing means for the muzzle end of said barrel, saidsealing means comprising: a tubular adapter having its rearward endsealingly connected to and enveloping the outer wall of the muzzle endof said barrel; a sealing sleeve having its rearward end sealinglyreceived in and enveloped by the forward end of said adapter andextending forwardly therefrom, said adapter and said sleeve providing abore forming an extension of the barrel bore, said sealing sleeve beinglaterally unconfined between its forward end and the forward end of saidadapter and having a weakened portion extending therearound disposedadjacent the forward end of said adapter, said sealing sleeve furtherhaving a counterbore in its forward end providing a relatively thin sidewall; and a sealing disc inserted in and sealingly retained in saidcounter-bore, said sealing disc being adapted to be penetrated by thehigh kinetic energy missile, the relatively thin side wall and weakenedportion of said sleeve being adapted to absorb, by permanent deformationthereof, destructive energy occasioned by the firing of said missile andthe transition thereof through said sealing disc into well fluid,whereby said barrel is prevented from being damaged.

References Cited in the file of this patent UNITED STTES PATENTS 44,631Hull Oct. 11, 1864 1,266,087 Williams May 14, 1914 2,216,144 TurchekOct. 1, 1940 2,489,568 Ferhat Nov. 29, 1949 2,649,736 Phillips Aug. 25,1953 FOREIGN PATENTS 581,817 Great Britain Oct. 25, 1946

